A particle beam therapy is widely practiced as treatment of irradiating a lesion area (e.g., cancer) of a patient with a particle beam such as a proton beam and a carbon ion beam. As one of such particle beam therapies, there is a known technique in which a patient lying on a treatment bed is positioned and irradiated with a particle beam in a treatment room formed inside a large rotation mechanism (hereinafter, referred to as a gantry).
In a particle beam treatment apparatus having such a gantry, by rotating the irradiation port fixed to the gantry or displacing the treatment bed in the treatment room, a lesion area of a patient is irradiated with a particle beam from an arbitrary direction.
The treatment room formed inside the gantry is formed by a moving floor that is configured of a horizontally flat floor surface and the other surfaces having an arch shape along the inner circumference of the gantry so as to form a D-shaped cross-section regardless of the rotational position of the gantry.
The treatment room is formed by the moving floor in which the horizontally flat floor surface and the arch surface are maintained while the irradiation port is fully rotated around (i.e., by 360°). This improves workability of a technician in the internal space of the treatment room and reduces the feeling of mental pressure of the patient lying on the treatment bed.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 1999-47287
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2001-353228
[Patent Document 3] Japanese Unexamined Patent Application Publication No. 2011-156263
When a device is installed on this moving floor, a cable for inputting and outputting signals to this device and another cable for supplying electric power pass through the through-hole provided in the gantry and extend to the outside thereof.
Since the moving floor has a D-shaped cross-section as described above, the distance between the position of the device provided on the moving floor and the position of the through-hole provided in the gantry depends on the rotation angle of the gantry and is not constant.
Thus, when the cables are caused to rotate in conjunction with the rotation of the gantry, as the gap between the moving floor and the gantry becomes narrower, there is a higher possibility that an extra length of each cable is generated in this gap and the cable(s) is tangled so as to be broken or the stable rotation of the gantry is inhibited.
In view of the above-described problems, it is an object of embodiments of the present invention to provide a particle beam treatment apparatus which is excellent in stability of rotating operation by devising the wiring of the cable(s) connected to the device installed on the moving floor.